1. Field of the Invention
The present invention relates to a semiconductor device, and, more particularly, to a semiconductor device having leads protruding from only one surface of a flat package, such as a PGA (Pin Grid Alley) or DIP (Dual In-line Package).
2. Description of the Related Art
Semiconductor devices of the PGA and DIP types have leads arranged along only one surface of the package, making their mount on printed circuit boards easier, and are thus popular today. To make the package of this type of semiconductor device smaller, a plurality of leads 103 are arranged close to one another on the bottom of the package 101, as shown in FIG. 6. The leads 103 are inserted in holes in a printed circuit board (PCB) 120 and are soldered to the printed circuit. Thereafter, the leads of other electronic parts or the like are soldered to the printed circuit.
As the number of the leads 103 of the device increases, the number of printed circuits increases accordingly, increasing the area of the PCB 120. This naturally requires greater space to accommodate the PCB 120, enlarging the general PCB assembly.
The semiconductor device disclosed in Japanese unexamined utility Model Publication No. 23087/1987 has an IC socket situated between a PCB and the semiconductor device. This IC socket has leads for connection to the PCB and leads for connection to other electronic parts. This design requires no intervention of the PCB to connect a PGA to the other electronic parts.
In this case too, the PCB assembly is enlarged by the space of the IC socket.